A Study Of The Medial Temporal Lobe In High-risk And Established Schizophrenia Using T2 Relaxometry
Funder
National Health and Medical Research Council
Funding Amount
$358,245.00
Summary
Neurodevelopmental models of schizophrenia suggest that this disorder is associated with a structural brain abnormality present from very early life. This model predicts that brain changes are present before the onset of schizophrenia, and do not change. Our work supports the idea that damage is present from the outset of illness - however, this damage was not evident in a high-risk group of individuals who later developed psychosis. When these patients were rescanned after the onset of the illn ....Neurodevelopmental models of schizophrenia suggest that this disorder is associated with a structural brain abnormality present from very early life. This model predicts that brain changes are present before the onset of schizophrenia, and do not change. Our work supports the idea that damage is present from the outset of illness - however, this damage was not evident in a high-risk group of individuals who later developed psychosis. When these patients were rescanned after the onset of the illness, they exhibited reductions in the volumes of structures that are regarded as critical to the symptoms of schizophrenia. The lack of structural changes in this group before the onset of psychosis may have a number of possible explanations. However, it may be that a number of factors produce the observed changes in the temporal lobe in schizophrenia. Thus, high-risk subjects may have a vulnerability to hippocampal damage that becomes apparent during the transition to psychosis. In order to explore this, our study will examine changes in the hippocampi in three groups of patients, and compare them with matched normal control subjects. The patient groups are: (i) individuals at high-risk, (ii) first-episode psychosis patients and (iii) patients with chronic schizophrenia. The study will rescan the high-risk group to examine hippocampal changes once they have become psychotic. T2 relaxometry is a non-invasive way to examine whether changes in the brain are present in patients with schizophrenia from the outset of illness. T2 will also let us examine the high-risk individuals to see whether such changes are also apparent premorbidly. Using T2 we will be able to examine the nature of these structural changes and assess what processes are in evidence. Our MRI findings present a challenge to the neurodevelopmental hypothesis of schizophrenia. The use of T2 in this study will allow a thorough examination of these findings and will have major implications for this hypothesis.Read moreRead less
Delineating The Anatomical Correlates Of Neurocognitive And Psychomotor Dysfunction In Depression By FMRI
Funder
National Health and Medical Research Council
Funding Amount
$388,340.00
Summary
Severe depression is characterised by slowing of mental and motor abilities. Previous research by our group indicates the role of small frontal and basal brain regions in the regulation of these abilities. This research will extend our previous studies by providing new information detailing the underlying physiology of behavioural and structural abnormalities in patients with severe depression. Emerging research by our group and others suggest that some types of severe depression in later life a ....Severe depression is characterised by slowing of mental and motor abilities. Previous research by our group indicates the role of small frontal and basal brain regions in the regulation of these abilities. This research will extend our previous studies by providing new information detailing the underlying physiology of behavioural and structural abnormalities in patients with severe depression. Emerging research by our group and others suggest that some types of severe depression in later life are due to undetected forms of cerebrovascular disease. If we are able to demonstrate that the key features of severe depression of this type (psychomotor, attentional, memory and executive disturbance and global disability) are related to such brain changes this may lead to a major breakthrough in the prevention and treatment of these disorders. A new type of brain imaging technology called 'functional Magnetic Resonance Imaging' (fMRI) permits simultaneous investigation of the structure and function of small areas of the brain. As the technique does not use radiation and can be performed while the patient is completing mental tasks, it can be used in repeated experiments. Consequently, it permits description of brain changes (areas of activation) that occur during specific mental tasks. Therefore, if we are now able to use this technique to extend our previous clinical and imaging studies we will be able to test whether some forms of late-life depression are due to undetected brain changes.Read moreRead less
Early Detection Of MCI And Dementia Using Multidimensional Analysis Of Structural MRI By Computational Methods
Funder
National Health and Medical Research Council
Funding Amount
$583,601.00
Summary
Dementia in elderly is a major public health problem, and mild cognitive impairment (MCI), is even more common. We propose to use recent computational anatomy algorithms from our group to develop novel multidimensional imaging biomarkers for early detection of brain anatomical changes due to MCI-dementia. We aim at identifying early signatures of MCI-dementia, thus making early treatment possible. The completion of our research will provide clinicians with new methods for the early diagnosis.
An Extended Follow-up Of Stroke Patients For Cognitive Impairment And Neuropsychiatric Disorders: Sydney Stroke Study
Funder
National Health and Medical Research Council
Funding Amount
$321,800.00
Summary
Vascular Dementia (VaD) is the second most common cause of dementia after Alzheimer's disease. In fact, it may be a preventable cause of dementia. Yet it has been relatively neglected by researchers until the last decade, which has seen an upsurge of interest in this disorder. There is no consensus on the criteria for dementia. The profile of early cognitive impairment due to vascular factors is still poorly understood, and the longitudinal course of VaD as defined by modern criteria has not bee ....Vascular Dementia (VaD) is the second most common cause of dementia after Alzheimer's disease. In fact, it may be a preventable cause of dementia. Yet it has been relatively neglected by researchers until the last decade, which has seen an upsurge of interest in this disorder. There is no consensus on the criteria for dementia. The profile of early cognitive impairment due to vascular factors is still poorly understood, and the longitudinal course of VaD as defined by modern criteria has not been studied. There have been few studies of the progressive changes in MRI in patients with cerebrovascular disease. The overlap of VaD and Alzheimer's disease (AD) remains a problem for taxonomists and clinicians. One approach to the study of VaD is to examine a high risk group of subjects longitudinally to determine the early features, the risk factors and progressive changes. With this in mind, we began studying a cohort of stroke patients who are at high risk of VaD, in 1997-1999, and are following them longitudinally. The follow-up is now in its third year, and three neuropsychological assessments and two MRI-MRS scans have been performed. We propose to extend the follow-up to 5 years, with repeat neuropsychiatric, neuropsychological and MRI-MRS investigations, and wherever possible to necropsy, to determine the nature of vascular pathology that underlies cognitive impairment. Our cohort of stroke patients is arguably the most comprehensively assessed such cohorts internationally, and presents an excellent opportunity for a long-term follow-up study.Read moreRead less